The present invention relates to an electrical machine with a grooved base body provided with conductors, as well as to a method of producing electrical machine, and a device for producing the electrical machine.
Electrical machines as a rule have at least one base body composed of a lamellised, soft-magnetic packet of metal sheets, which carries a winding. The base body is a part of a stator or a support, and/or a part of a rotor or a runner or an armature, wherein the conductors of the winding are inserted in the grooves of the packet of metal sheets in an insulated manner and connected with one another. Stator and rotor cooperate through a so-called working air gap. For avoiding oscillation noise of the winding it is important to fix the conductors in the grooves as reliable as possible. Moreover, the conductor fixing for rotors which rotate at high speeds is important for avoiding conductor movements under the action of centrifugal forces, since it can lead, in addition to other issues, to imbalance on the rotor.
For this purpose it is known to fix the conductors in the grooves by an impregnating resin. This method is not only environmentally unfriendly, but also requires considerable apparatus investments as well as sequential process steps for removal of the impregnating resin on different regions of the machine, such as for example on a commutator, on bearing points and on an outer periphery of the rotor.
For avoiding these disadvantages it was proposed in the patent document DE 100 49 699 A1 to fix the conductors in the grooves of an armature packet of metal sheets of electrical machines by deformation of the material which limits at both sides the slots of the groove, against the groove bottom. Since the varnish-insulated conductors in many cases have a round cross-section for cost economy, in these solutions a relatively small groove packing factor is provided, so that the power of the machine is limited and/or the dimensions of the armature are increased. It is also generally known in order to increase the groove packing factor of the stamped conductors to use the conductors with square, rectangular or oval cross-sections in the correspondingly formed grooves. This is however expensive since for the grooves with several conductors the conductors must often have different cross-sectional shapes. This means that an expensive processing technology and thereby complex and additional machines or manufacturing stations must be provided. Furthermore, with an automatic manufacture, a conversion from round conductors to pre-formed conductors with conductor portions adapted to the groove cross-section can not be performed in an economical manner.